New "On Panel Activate" event akin to "On Page Load"

As rich web applications increasingly use AJAX-type interactions to load portions of the page dynamically, the "on page load" event becomes less and less useful as a trigger for events specific to a particular screen region.

Justinmind's "Panels" are a fine way to simulate these interactions, but would be even more powerful and flexible if there was an "On Panel Activate" event trigger akin to "On Page Load" (and possibly an "On Panel Deactivate" to match it, akin to "On Page Unload".)

I know that I can add "on click" and other events to the components that use "Set Active Panel" to trigger the panel changes, but that leads to a lot of duplication of effort and difficulty in maintaining a complex prototype.

Better would be to detect when a panel activates and perform the initialization or other actions pertinent to that panel becoming active.